Electrically propelled wheel chair



March 13, 1951 c, GUYTON 2,544,831

ELECTRICALLY PROPELLED WHEEL CHAIR Filed Sept. 3, 1948 5 Sheets-Sheet l Arthur 0. Gag Ion VENTOR.

W 'Mt March 13, 1951 A. c. GUYTON ELECTRICALLY PROPELLED WHEEL CHAIR Filed Sept. 3, 1948 5 Sheets-Sheet 2 Arthur 6. Guyion INVENTOR.

9 BY @wm fi fim Fig.2.

March 13, 1951 A. c. GUYTON 2,544,831

I ELECTRICALLY PROPELLED WHEEL CHAIR Filed Sept. :5, 1948 s sheets-sheet 3 I N VENTOR.

March 13, 1951 A. c. GUYTON 2,

ELECTRICALLY PROPELLED WHEEL CHAIR Filed Sept. 3, 1948 5 Sheets-Sheet 4 Arthur G. Guyfon March 13, 1951 A. c. GUYTON ELECTRICALLY PROPELLED WHEEL CHAIR Filed Sept. 5, "1948 5 Sheets-Sheet 5 Arfhw" 6. Guy ton INVENTOR,

Patented Mar. 13, 1 951 UNI TED STATE-S PAT ENT OFFICE ELECLBRICALLY PROPELLED WHEELiGHA-IR Arthur C. Guyton, OXfordPMiSS.

Application September 3, L948,'S.erialfNo 47,423

13 Claims. 1

This invention relates to electrically propelled wheel chairs and -it:h;as forits primary purpose to provide a combined propelling and steering mechanism controlled :by :a single :mastercontrol switch, which-enables the occupant of the chair to direct :the movement of the chair completely by slight -movementsto'f a lever.

-Electricallydriven wheel chairs are known but they require, as a rule, 1theuse ofiaxsteeringllever orother mechanism :directingasteering or guiding Wheel 'in addition to the mechanism *which determines the backward or forward idriving movement :of the :chair and the stopping and starting-of the Wheel movement. Moreover most of 'these mechanismshave to be built into the chair and are not removable or interchangeable.

It is the imain .ipurpose .of the invention to eliminate :the specialisteering mechanism an'd to use a single 'control'mecha nism :for regulating all directional movements'and the'driving or propeli lingimovement as well'as the direction of such propelling movement.

Itiisaiurther purpose o'f theiinventionto provide :a :master control switch provided with a single control lever movable in different directions wheel chair which permits to either drive both 'wheels 'or to lock one wheel while driving the other in the desired direction-of propulsion, this simultaneous locking and propelling of the two wheels and the resulting difference in speed of the Wheels being used for the changeo'f the direction or" driving.

It is a further object of the invention to provide means for maintaining frictional engagement between the rnain driving Wheel and a driving roller which is rotated by means of an electromotor, which engagement may be released, temporarily for steering purposes for each wheel separately.

It is a further object of the invention to provide combined frictional driving and braking means adapted to act on each of the maindriving-Whels separately operable electromagnetic means for lifting the l-frictionalsengagement[between a driving roller engaging one of the main propulsion wheels" of the wheel chair and .for simultaneously applying a braking member, said 1 driving .ioller 1' being driven by an electromotor othe current .sup-

ply andith'e directionof ilowpi whichis controlled by a master control switch saidswitch simultaneouslyrcontrollingthe said-electromagnetic devices, said controlling lmeans being ;.-so arranged that simultaneous control of the driving and brake action may b obtained by asingle master vcontrol lever of the im'asterscontrol switch.

.-It is "a =further -:object of the invention-to provide means such as a number of :relay switches,

- changing the ?direction of current flow through the electromotor driving the frictional driving rollers acting on the main'driving wheels I of .the wheel chair, which :relay switches :are controlled by the master-control switch.

it isxasiurthercobjectzo'f the inventionto provide cfr'rctional driving means' iorathe' ma-indrivewheels of a wheelichair which *are driven by :thesame shaft, .rotated dcyzan selectromotor in one L01 ithe other direction, tthese'drivingmeans being associated with frames carryingebrakingmeans which i'rames are-acted :uponizbyzsolenoidscontrolled by a master control switch, which alsoacontrols the starting, stopping and the 1 direction of notation of the electromotor, each of said solenoids by "elastic deformation of the driving shait moving the driving roller :of :one side :out :of engagement "and the brakezmember into engagementzwithathe main driving wheel, thIIS DGYmitCiII-g waking :d'f dine main driving whee'l and driving :of the other m'ain driving wheel, iupon 'energization (of one 'of the solenoidssaid energiz'ation thus producing-a cha'nge' in the' hea'dirig or angular 'directiondf the wheel 'c'hair.

A further object o'f 'the in'vention consists i'n providing a further switchingimeansziorphanging "the speed of 'the eiectromotor.

":Fu rtherand more 's'p ecific: objects will besappar- "ent rrom the f-ollowing specification.

The invention is illustrated in sthesaccompany 'in'g draw' in'gs, 'sho'wing "one "ler'nbodiment anereor and several modifications of the details used, by way of example. It is to be understood however, that the example shown serves mainly the purpose of explaining the principle of the invention and the best mode of applying said principle, but does not show the sole way of practical application of the invention. Modifications of the example shown, some of which will be described or foreshadowed by the detailed specification or will be obvious to the expert skilled in the art, are therefore not necessarily departures from the invention.

In the drawing:

Figure 1 is an elevational side view of an electrically propelled invalid chair, according to the invention.

Figure 2 is a perspective view of the electric driving mechanism when viewed from the rear of the chair.

Figure 3 is a sectional plan view of the chair, the section being taken along line 33 of Figure 1.

Figure 4. is an elevational side view of the control switch unit mounted on the chair which contains all the means necessary for propelling at different speed, and for selecting the direction in which the chair is intended to move.

Figure 5 is an elevational sectional view of the same switching unit the section being taken along line 55 of Figure 4.

Figure 6 is a plan view of the switch unit shown in Figures 4 and 5.

Figure 7 is a cross sectional plan view the section being taken along line of Figure 4.

Figure 8 is an elevational view of one of the solenoids which regulate the application of the drive wheel and of the brake.

Figure 9 is a sectional elevational view of said solenoid, the section being taken along line 9-9 of Figure 8.

Figure 10 is a perspective view of the locking mechanism holding the driving unit on the chair.

Figure 11 is a sectional elevational view of one of the drive rollers.

Figure 12 is-a diagram of the electric connections.

Figure 13 is a partly sectional view of a clutch coupling to be used in connection with a modification of the braking and driving unit.

Figure 14 is an elevational sectional side view of a double relay switch adapted to close one pair of contacts while opening a second pair.

Figures l5, l6 and 17 illustrate diagrammatically three different phases of the position of the driving roller and brake. 1 Figure 18 is a diagram showing a modified form of the master control switch or stick.

Figure 19 illustrates a further modification of the arrangement illustrated in Figure 13.

The electrically propelled wheel chair according to the invention is based on the principle to govern all its movements by a single master control switch lever or stick. This movement, therefore, controls the angular direction as well as the forward or backward movement of the chair, the starting, stopping and braking. The said master control switch lever or stick therefore forms the steering mechanism as well as the drive control and brake application mechanism.

Briefly stated, the entire control of the chair is concentrated in this switch lever and is performed by moving said lever into different directions. Additional switches are merely necessary to out out the current altogether and to change the speed of driving, but even the latter switch may be seated on or connected with the master control lever or stick. The same master control lever may also be used for applying the brakes and for cutting out the motor for bringing the wheel chair to a sudden stop, by moving it axially for example.

This principle of using a substantially unified control of the chair by means of a single lever instead of using a separate steering mechanism and a separate motion control mechanism, supplemented by some further controls of minor importance is applied by using separately controllable driving and braking devices for each propelling wheel, which permit driving of one wheel while the other is under the influence of a brake so that the steering may be obtained by producing differences of speed between the wheels resulting in a turning or pivoting of the chair around the wheel which is held back while the other is driven.

Referring now to the embodiment shown in the drawing it will be seen that Figure 1 shows a standard wheel chair construction for invalids which need not be described in detail and which includes a frame 20 made of welded metal tubes carrying a seat 2|, a back 22, a foot rest 23 supported by-main driving wheels 26 provided with hand rims 30 and rotatably mounted on an axle pin 29. Moreover the chair is provided with front rollers 28 mounted in a sheaf 33 turning around an axle pin 21. The vertical tubes or struts 32 which carry the axle pin 29 end in push bars or handles 24 while the vertical struts 3| are bent horizontally and form a support for the arm rests 35 covering the said horizontal portions.

The lower portion of the framework consists of a pair of horizontal tubes 25 which may or may not be joined by a transverse brace.

As above stated the wheel chair which has thus far described is a standard construction to which the invention may be fitted, but which is not changed or modified when the invention is applied. It seems therefore unnecessary to describe it further.

The driving mechanism for this standard wheel chair comprises a frame 40 made of a band or angle iron and which comprises two parallel sections 4| joined by a transverse section 42 at the end and by further transverse members 44. The two parallel sections 4| carry angles or a band iron with outwardly bent flanges or ends 43 at each side, said ends or flanges projecting outwardly at right angle to the section 4| of frame 40.

The flanges or bent ends 43 are provided with circular cuts 45 fitting the tubular frame members 25 of the wheel chair frame and when said flanges have been secured on the tubular members it will be clear that the entire frame 40 is firmly held on the chair with the driving members of the drive mechanism in engagement with the wheels of the chair as described below.

To secure it in its position the mechanism shown in Figures 3 and 10 is used. It consists of a locking tongue 45 with a bent end 4'! adapted to be drawn against the vertical strut or tube 32 by a small lock lever 48 to which it is linked eccentrically at 49. The lever 48 is pivoted at 58 to a Z-shaped bracket 5| fixed to the band iron section 4| near the flange 43. The eccentric link or look lever 48 is provided with a thumb piece 52 at its end and when turned this thumb piece pulls the end of the locking tongue 45 against the vertical strut 32 securing a firm holding. The

.lo'ckiever 46 finally abuts against the projecting flange and by-virtueof the eccentricity of the pivotlink &9 the lock lever, once it has been turned downwardly, will remain locked in its position without being capable to turn back. The two lock mechanisms on both sides of t'he frame 40 therefore lock the said "frame securely to the frame 2530f the wheel chair, thereby "securely to the 'frameZil of the wheelchain the'reby'sec'uring automatic engagement of the driving members of the drive mechanism with-the wheels as described 'below.

Thefframe '40 "supports practically the entire drivingmech'anism. Thismechanism consists of an electromotor 60'h'eld bysuitable longitudinal and transverse struts and shields which drive'sa 'shaft'TIiI carrying a pulley 62. iThe motormay bejprovided'with a'suitable gear box if necessary tobrin'g the'sp'eed of lthepulley to th'ede- 's'ired value at "the maximal "or "normal motor 1 la'tter'beingkeyed to the shaft by means-of the set screw "I6.

H The driving roller 86 has'aV-shaped groove 11, the profileor cross'seotion of which shows 'afiat portion flanked by inclined walls. This groove therefore may engage the standard driving wheel of a wheel chair and establish frictional contact with .the peripheral portion of the tire'on the said wheel.

The frictional contact isautomatically established when the frame ll) is inits place and is locked on the tubes 25 of the wheel chair.

The frame "I5 carries moreover a brake roller "18, theapplication of which-against the tire produces a'strong braking actionby friction which a'rrests'the driving wheel. This brake roller may beheld on the frame by means of the bolt 19.

Each'frame I5 is connected with 'a lever arm- 8 2 pivoted at 9 to the core BI of a solenoidllll. The

connection of thelever arr n82 with the frame I5 isma'de atone end thereof,"such as the endcarrying thebolt T9 and'said-connectionmay bemade by mean-sof the nut holding the bolt in-place. -A

brace'orstrut 83 iSl'QOIBQVEPLlSG Cl to connectan intermediate point-84 on the lever 82'with'the other end of the frame, where-"the brace or strut "83 is fixed by means of athreaded bolt "85. movement of the lever produced by "the solenoid hastherefore the tendency to pushthe' lower portion o ffthefra'me outwardly, and away from the solenoid while the'said movement of the-lever 8 2 "hasalso "the tendency to move theuppe'r point 19 of the frame inwardly'towards the solenoid ilfl. The "solenoids 9c are provided with coils 93 "and in theexample shown each coil surrounds a "s1eeve95 passing through the center of the coil which -serves as a holder for the solenoid. The

"sleeve'95 for this purposeis closed at it's lo'wer 'end"by"a p1ug 9l and-a bolt 66 passes'through it "andsaid plug,'carrying the solenoid structure. "The bolt '86 is'fixed to theband ir'on fil of --the frame.

The plug 91 also serves-as an abutment for the spring $8 in'serted into the "sleeve :and' pressing against'the core S-I "The-sleeve in "its upper portion 1's "provided with a sl'o-t 99 permitting the passageof'thebar 82.

The frame 49 moreover carries a storage b'attery 'I 06, which may beheld on transverse ba rs (not shown) by meansof the'two posts ll with bent ends I62 through which-screw bolts I63 pass which are applied againstthe upper edge of the battery. Thebattery'isprovided with-a charging unitfso thatit can be'recharged when exhausted by plugging in-a wall plug IIO into'the'outlet of "an A. C.-ne'twork. This unit which is also indicated in the diagram Figure '12 comprises the transformer I I2 and the rectifier set H4.

The regulation of themotor speed is obtained by-means of a resistance '-I'I6-coop'erating 'with'a frel'ay switch "I I8 arranged in parallel thereto. When the relay switch-is-energized theresis'tan'ce is short -circuited and the motor runs at maximal speed. When the relay switch is deeper- *g'ize'd the resistance is in the supply circuit of the motor 60 and thereby the speed of the motor is reduced.

The control of the'direction of rotation of the motor is effected by a number of relay switches I26, I2I, I22, 123 each controlling a set of contacts. These relay-switches may form a single constructional unit as shown in Figure -2 mounted'on a transverse bar ld. As the relay switches are only operated alternatively as will be "explained below "they may be replaced twin solenoid switches I36 such as shown in Figure 14 with two-solenoid coils 12d, I25 acting one common movable core I26 which carriesza contact bar I2! with contacts 123, E29 which may cooperate with fixed contacts I3I, I32, I33, I 34. The core I 26 may be held in'a neutral position-by springs I35 held within a sleeve of nonmagnetic material within which the core is slid- "ing.

The entire electric driving mechanism'rnounted'on the frame '49 -rnay be-concealed and pro tected "by a cover hi6 such as shown in Figures 1 and 3. Merelythe shaft "Iii, drive wheel-65 and theassociated parts-such'as the frames-T5 and rollers 66 are thereforeoutside thecover and are "visible and accessible so that the electrical part of the unit is fully protected against accidental damage.

"Ihe controlo'f the wheel chair by its occupant is *exercised as hasbeen explained by 'a single master control switch lever I56 which forms simultaneously the steering mechanism,

' 'the'reversing-mechanism and the stop and start mechanism, as far asinte'rmittent stopping'and starting is concerned. The master control witch generally indicated at I 25 is preferably mounted on'the arm supporting rail 36by means of a'U shaped bracket I36 carrying a clamping screw F31. The said clamping screw is provided with a clamping disk I38 which may be'pressed against the arm supporting rail.

The master control switch I45 "comprises a cover plate I66 of insulating material and a frame "consistingof a bent plate I 39, with an upper horizontal plate'portion I4I attached :to thecover pla'te I66 byrivets I6Iandresting on -the arm support rail 36 and a lower horizontal portion I42, the two horizontal portions being joined by a ver tical member which carries "the "supporting bracket I36.

In the lower horizontal plateportion I42 an insulating bushing II4-3 is inserted and-through thi's bushing ascrew bolt I44 is threaded which ass racer also forms a terminal post for connecting it with a current carrying wire and which is fixed by a number of nuts. Said screw bolt carries an elastic rod or spring member I48 movable in all directions against some elastic tension. The spring member in its turn carries the switch arm [59 which comprises a cylindrical metallic portion l! surmounted by a handle i532 of insulating material on its top.

The cylindrical member [at passes through an outer cylindrical casing I5 5 which may be of insulating material and in the interior of which four contact leaf springs I55, i526, lE/i, I53 are arranged, two contact leaf springs forming a pair facing each other and the two pairs being arranged at right angle to each other. :The leaf springs thus are disposed so as to form part of a square surrounding the cylindrical metal cylinder liil. The leaf springs are preferably disposed across the four main directions of movement as viewed from the position of the occupant of the chair. Each leaf spring is COD-.- nected with a terminal post use with which an electric connection may be made so that each leaf spring is connected with a separate circuit or part of a circuit.

It will therefore be clear that when the master control switch lever IE6 is moved by the occupant of the chair in a forward direction the metallic switch portion it'ii will make contact with leaf spring 55 located in front and when the handle is moved to the right, contact will be made with spring ltd provided the switch is mounted on the right arm support rail, and is operated with the right hand of the occupant.

The switch may also be moved in a diagonal or under an angle to the forward and backward direction and in this case the member Edi may make contact for instance with both contact springs I55 and 156.

The cover plate :63 also carries two switches I64, I65 which may be of the usual type and are shown as tumbler switches. One of said switches controls the admission of current to the drive mechanism. The other switch controls the speed. Their function in detail will be seen from the diagram Figure 12.

The diagram of connections shown in Figure 12 explains itself as the reference numerals are identical with those above explained. only be added that the reversal of the motion of the chair is obtained by reversing the motor (iii; the latter operation is performed by revers ing the current direction in the field (or in the armature) winding. The ground connections indicated in the diagram are return connections obtained by means of the chair frame.

The operation of the arm chair by means of the single master control lever is the following.

The switch m5 which cuts out the entire current supply must first be closed in order toput the chair into condition for action. When this has been done the master control lever iilS is connected with the battery Hill by conductor iia'i, but no movement will occur as long as the master control lever is not moved. Let it be assumed now that straight forward movement is intended; then the occupant of the chair moves the master control lever 5% straight forward making contact with contact spring iEE. This closes a circuit through conductor H56, master control lever E50, contact spring i552, conductor i6! and relay switches R23 and 52f. Relay switches i2o and i2! close their contacts and an energizing circuit for the motor 69 is thereby It may i closed. If the occupant leaves switch I64 open because he wants to drive the wheel chain at low speed this circuit may be traced from battery lite, conductor I53, resistance H6, conductors I68 and ill} through closed contacts of relay switch 52%}, through field winding ill of motortl], closed contacts of switch relay l2! through armature M2 to ground. The motor 68 starts to turnin a forward direction, with the current flowing through the field winding in the direction of the arrow.

Should the occupant have desired a backward movement he would have moved the master control lever backward contacting spring l5? and closing a circuit through relay switches I22 and i223, through conductor H3. The current through the motor, instead of passing conductor I'm, will then flow through conductor I'M and through closed contacts of switch H23 and conductor lit through the armature of motor St to ground. The current through field winding Ill being reversed the motor til will rotate in the opposite direction.

Rotation of the motor drives shaft Bl, pulley 62, pulley 55 (Figure 2) and shaft re. The ro-j tation of shaft iii rotates the rollers Sit which are in frictional contact with the tires of the wheels 26 and the wheels will thereby be driven in the desired direction.

Let it be assumed now that the occupant of the chair while going forward wants to turn to his right. He then moves the master control lever diagonally so that said lever touches both contact springs E55 and i556. Thereby two circuits are closed. One of them being the motor circuit which has already been described. The second circuit is the circuit l'il' of the right sole;- noid til marked Gila in Figure 12. This solenoid will attract its core and will lower its lever 82. Thereby as seen in Figures 15, 16, 17, the frame 75 with the grooved drive roller 8%] and the brake roller i8 is subjected to a force which pushes the lower part of the frame away from the wheel, while the upper part is drawn towards the wheel. The movement thus imparted is only slight but it results in pressing the brake roller against the tire of the wheel while the roller SE] is moved out of engagement. The right wheel is therefore subjected to a braking action while theleft wheel moves ahead and the chair is thus turned to the right. 4

The movement of the frame 75 is based on the resiliency of the shaft EB and shaft bearing arm 68 and on the slackness of the belt 66, but

' experience has shown that the minute movements which are necessary are absorbed by the resiliency of the members without any difficulty.

It has been mentioned that switch [54 serves the purpose of changing the motor speed, so as to be able to drive the wheel chair either at a low or at a higher speed. This result is obtained by means of relay switch H8 which permits to short circuit resistance i It. It will be clear that the closure of switch i6 5- located near the master control lever 556 energizes relay switch H8 over conductor its and both switches E and I64 and the energization of the relay switch in its turn closes the circuit branch i559, located. in parallel to resistance H6. Therefore the re.- sistance is no longer active and the amperage of the current flowing through motor 6E] is increased, resulting in a higher speed of rotation.

A modification of the above described arrangement is illustrated in Figure 13. According to this modification the shaft NJ car-ryvcontacts I99; 289; 28I-. i circuit branch. supplying the-motor with current and are closed in the normal positionof the.

ing the pulley 65 is held in. bearings I3 and is coupled with the-shaft sections I88, I8I- carrying the drive rollers 80 by means of magnetic couplings I82, I83 which also. operate the braking means. The couplings I82, disks I84, keyed to the shaft I8 and further ferromagnetic armature disks I85 frictionally or otherwise engaging disks I84 and seated on shaft sections I88 and I8] respectively. Disks I 85are keyed to the shaft sections but are displaceable. They are pressed towards disks I84 by means of disk or cup shaped springs I81, held by a collar I86 fixed on the shaft sections I80, I8I.

At the rear of disks I85 annular brake linings I88 are provided, cooperating with similar annular linings I89 on the annular front ends of electromagnet housings I 92 which, preferably are fixedly held on brackets I9I fixed to one of the transverse struts of the frame.

The magnet housings I92 have the shape of cylindrical cups arranged coaxially withv the shaft sections I88, I8I. They contain the coils I98, I98a which are also arranged coaxially with the shaft sections I8, I88, I8I.

It will be obvious thatthe. ferromagnetic disks I85 form the armature of the electromagnet and are attracted by the magnetic field set up in the housing and passing through the disks towards the former. As long. as the electromagnets I99, I98a are deenergized the springs I8I press the armature disks I85 towards the coupling disks I84 of shaft. I8 and maintain a-coupling between the shaft section I88 or I8I and shaft I0. When the electromagnet 190 or I 99a is energized the armature disk I85 moves toward the electromagnet housing I92 and isdisengaged from frictional or other contact with disk I84.

Simultaneously the brake lining I88 is pressed towards lining 189 on the front end of the electromagnet housing and the shaft section (I88 or I8I) is effectively braked, thereby also braking the main drive wheel engaged by the roller on said shaft section.

It will be clear that the electromagnets I99,

I98a may be connected in the same way in vwhich the solenoid coils 98, 98a are connected,

;-panied by a breakingof themotor circuit with- 'out any additional manipulation. As seenfrom Figure 18 the master control lever I 59in this case is mounted on a collar- I95 which is spring pressed, so that it maybe moved downwardly against the actionof spring. I 96.

The lever is provided with.two. contacts I91, I98 each cooperating with; a' -set of stationary Contacts 288 are in a lever Contacts I99 and 2M are'connected with the two solenoids 98a; 901), respectively. Upon depression of the master. control: lever both'solengids. 99a and 991)- are energized so. that the brake. rollers are. applied on both wheels, while I83 comprise l0 simultaneously the supply circuit for. the motor is. interrupted.

The main advantages of the wheel chair reside in its extreme maneuverability by means of slight movements of the handwhich may effect control while the. arm rests on the arm support rail. No. additional finger or foot control is necessary and no. moving of thearms, such as usually required to steer the chair need be used. All the maneuvering. may be done by moving the master control lever or stick slightly. In spite. of this type of. control centered in. a single control. lever or stick simultaneous double operations. such. as applying brakes while breaking the motor circuit, applying the brakes on. one side while driving. in any direction on the other sidemay beperformed.

Moreover it. will be noted that the driving unit-is self contained. and may be removed from one. chair and. fixedlto. another. chair by an. extremely simple manipulation. without any preadjustment or the. like. Moreover. as stated the unit is. equipped. with. all recharging means. for the storage battery and may therefore be recharged. by unskilled persons and in many cases by the person using. the chain.

It will. be clear from the description. of the details. that many changes may be. made which will not affectthe. essence of the invention.

Having described the invention, what claimed as new is:

1. An. electrically propelled wheel chair with two. mainldriving. wheels, comprising a frictional driveroller for each main driving wheel, a braking means for each-wheel,electromagnetic means for. bringing said frictional drive roller and said braking. means alternatively into and out of operativeconnection with each wheel for steering and braking. purposes, an electromotor provided with. means for driving said frictional driving roller, operative circuits for said electromagnetic means andfor. said electromotor and a master control. switch with a manually controlled master control lever, carrying. a movable contact means, said switchbein'g further provided with a number of fixed control contacts adapted to be brought into operative contact with. the movable contact means upon movement of the master control lever for selectively closing the operative circuits of the. electromotor. and of the electromagnetic means- 2..Anv electrically propelled wheel chair with two. main driving wheels, comprising an electromotor, operative circuits for the same, a shaft driven by said electromotor, disengageable friction drive rollers on said shaft each drive roller being, normally in frictional engagement with one. ofsaidLmaindriving wheels, brake members for each mainv driving wheel carried by said shaft,.means.for. withdrawing each of said drive rollers. from. normal frictional. engagement with the driving, Wheel with which it is engaged and for bringing saidbrakemember simultaneously into. engagement. with the main driving wheel fiom. which.the..-drive roller was disengaged, a solenoid for. operating.v said means, anoperative circuit. for the solenoid, a. master. control. switch on: said chair. provided with fixed contacts, controlling. the. operative circuits. of the electromotor and the. operative circuits of each ofthe solenoids, said contacts being grouped around a center, and amaster control switch lever arrangedin the. center of the group: of fixed contactsandprovided with a movable contactadapted. to-bemoved. in all. directions and make contact alternatively with selected fixed contacts controlling propelling and steering of the wheel 3. An electrically propelled wheel chair with two main driving wheels, comprising an electromotor, operative circuits for the same, a shaft driven by said electromotor, disengageable friction drive rollers on said shaft, each normally in frictional engagement with one of said main driving wheels, frame members carried by said shaft, said frame members carrying brake members,

each adapted to be, applied against one of the main drive wheels, a frame rocking member for each frame member attached to the ends of each of the said frame members, a solenoid for operating each of said frame rocking members, an operative circuit for each of said solenoids, a master control switch on said chair provided with fixed contacts, controlling the operative circuits of the electromotor and the operative circuits of each of the solenoids, said contacts being grouped around a center and a master control switch lever arranged in the center of the group of fixed contacts and provided with a central movable contact adapted to be moved in all directions for making contact with said. fixed contacts controlling propelling and steering by the alternative and simultaneous energization of selected cirby said electromotor, frictional driving rollers on said shaft, each driving roller normally engaging one of the main driving wheels, a brake roller carried by said shaft near each of said driving rollers, electromagnetic means for applying each brake roller separately and for disengaging each of said driving rollers from frictional engagement with the main driving wheel, relay switches controlling the direction of current flow from the storage battery to the electromotor, a frame for supporting the storage battery, an electromotor shaft, driving rollers, brake rollers and relay switches, and locking means for locking said frame to the wheel chair frame thereby bringing the driving rollers into frictional engagement with the main driving wheels of the arm chair.

5. An electrically propelled wheel chair with a frame and two main driving wheels comprising a storage battery, an electromotor, a shaft driven by said electromotor, frictional driving rollers on said shaft, each driving roller normally engaging one of the main driving wheels, a frame surrounding each roller on said shaft, a brake roller on said frame, means for producing a rocking movement of said frame for simultaneously applying the brake roller and for disengaging the frictional engagement between the drive roller frame, thereby producing frictional engagement between the main drive wheels of the chair and the driving rollers on the shaft, a master control switch provided with fixed contacts each connected with one of the said relay switches and with further fixed contacts each controlling one of the said electromagnetic means, and a single,

hand-operated master control lever movable in all directions, carrying a movable contact connected with the storage battery and, when moved toward the fixed contacts, adapted to close the operative circuits either of one of the said relay switches or of one of the said electromagnetic means or, alternatively, to close the operative circuits of one of the relay switches and of one of the electromagnetic means simultaneously.

6. An electrically propelled wheel chair with a frame and two driving wheels comprising a storage battery, an electromotor, a shaft driven by said electromotor, frictional driving rollers on said shaft, each driving roller normally engaging one of the main driving wheels, a frame sur rounding each roller on said shaft, a brake roller on said frame, means for producing a rocking movement of said frame for simultaneously applying the brake roller and for disengagin the frictional engagement between the drive roller and the main driving wheel of the wheel chair, electromagnetic means for operating the above named means for producing a rocking movement of the frame, relay switches controlling the direction of current fiow from the storage battery to the electromotor, operative circuits for each of said relay switches and for each of said electromagnetic means, a master control switch provided with fixed contacts each connected with one of the said relay switches and with further fixed contacts, each controlling one of the said electromagnetic means, a single hand-operated master control lever movable in all directions carryin a movable contact connected with the storage battery, and, when moved towards the fixed contacts, adapted to close the operative circuits either of one of the said relay switches or of one of the said electromagnetic means, or alternatively to close the operative circuits of one of the relay switches and of one of the electromagnetic means simultaneously provided with fixed contacts controlling the said relay switches and with further fixed contacts controlling the said electromagnetic means and further provided with a single hand operated master control lever carrying a movable contact manually movable in all directions and adapted to close the operative circuits of each of the said relay switches and of each of said electromagnetic means singly or to close simultaneously a control contact of the relay switches and a control contact of one of the electromagnetic devices, a further relay switch controlling the amperage of the current flowing through the operative circuit of the motor and a further switch near the master control switch for controlling said last named relay switch.

7. An electrically propelled wheel chair with a frame and two main driving wheels comprising a storage battery, an electromotor, a shaft driven by said electromotor, frictional driving rollers on said shaft, each driving roller normally engaging one of the main driving wheels, a frame surrounding each roller on said shaft, a brake roller on said frame, means for producing a rocking movement of said frame for simultaneously apof the frame, relay switches controlling the direction of current flow from the storage battery to the electromotor, operative circuits for each 13 of. said relay switches and each of said electromagnetic means,a single master control switch provided with at least two fixed contacts facing each other each connected with one ofthe relay switches, controlling the direction of current flow to and thereby the direction of rotation of the el'ectromotor and the direction of movement of the main driving wheels of the chair, two further fixed contacts facing each other and arranged at right angle to the first named two contacts, each of said further fixed contacts being connected with one of the electromagnetic means applying the brake and disengaging the driving roller from the main driving wheel, all said fixed con tacts being arranged around a center, a single master control lever arranged substantially in the centerbetween thefixed contacts and provided with a central movable contact connected with the-storage battery, said celtral movable contact being out of contact with all the fixed contacts in the positionof rest of the master control l ver and being adapted to close either one of the operative circuits of the relay switches for a selected direction of current or, a selected circuit of one of said electromagnetic means or: alternatively;

closing simultaneously thev operative circuits of one of the relay switches and of a selected one of the-electromagnetic means, elastic m ans for holding said master control lever in its position of rest, said means being yieldable in all direc tions under manualpressure, the direction or" movement of the wheel chair being determined by the fixed contact or contacts to which the master control lever is moved for producing the closure of one or more of the aforesaid operative circuits.

8. An electrically propelled wheel chair with a frame and two main driving wheels comprising a storage battery, an electroinotor, a shaft driven by said electrornotor, frictional driving rollers on said shaft, each driving roller normally engaging one of the main driving wheels, a frame surrounding each roller on said shaft, a brake roller on said frame, means for producing a rocking movement of said frame for simultaneously applying the brake roller and for disengaging the frictional engagement between the drive roller and the main driving wheel of the wheel chair, electromagnetic means for operating the above named means for producing a rocking movement of the frame, relay switches controlling the direction of current fiow from the storage battery to the electromotcr, operative circuits for each of said relay switches and each of said electromagnetic means, a single master control switch for controlling the said operative circuit, said master control switch comprising at least two fixed contacts facing each other connected with relay switches, controlling the direction of rotation of the electromotor and thereby the direction of movement of the main driving wheels of the chair, two further fixed contacts facing each other and arranged at right angle to the first named two contacts, each of said further fixed contacts being connected with one of the electromagnetic means applying the brake and disengaging the driving roller from the main driving wheel, all said fixed contacts being arranged around a center, a single master control lever arranged substantially in the center between the fixed contacts and provided with a central movable contact connected with the storage battery, said central contact being movable towards the fixed contacts and out of contact with all the fixed contacts in the position of rest of the master control lever and being adaptedv to close either one of the operative circuits of the relay switches for a selected direction of current'or' a selected circuit of one of said electromagnetic means or, alternatively, closing simultaneously the operative circuits of'one of the relay switches and of a selected one of the electromagnetic means, elastic means for holding said. master control lever in its position of rest, the means being yieldable in all directions under manual pressure, said direction of movement of the wheel chair being determined by the fixed contact or contacts towards which the master control lever is moved for producing the closure of one or more of the aforesaid operative circuits, and further contacts on said master control lever closing the contacts of all electromagnetic means simultaneously for producing a-braking action on both main driving wheels.

9. In an electrically propelled Wheel chair as claimed in claim 8, means for interrupting the current supply to-the electromotor upon simultaneous closure of the contacts of both operative circuits of the electromagnetic means;

10. An electrically propelled wheel chairwith two main driving wheels, comprising an electromotor, operative circuits for the same, a drive shaft driven by said electromotor, a friction drive roller for eaohof said main driving wheels normally in frictional engagement with the same, means for controlling the transmission of power from said shaft to each of the drive rollers in engagement with the main driving Wheels, a brake mechanism for each main driving wheel, means for controlling both said power transmission controlling means and said brake mechanism for each main driving wheel and for making them alternatively operative, including electromagnetic coils, operative circuits for the electromotor and for each of said coils, and a single master control switch provided with fixed contacts connected with the operative circuits of the electromotor and the operative circuits of the coils respectively and further provided with a master control lever carrying a central contact movable in all directions towards the fixed contacts, said movable contact being thus adapted to control and to close selectively the operative circuits of the electromotor and of the electromagnetic coils, respectively.

11. An electrically propelled wheel chair with two main driving wheels, comprising an electromctor, operative circuits for the same, a drive shaft driven by said electromotor, a friction drive roller for each of said main driving wheels normally in frictional engagement with the same, means for controlling the transmission of power from said shaft to said friction driving roller, a brake mechanism for each main driving wheels. means for controlling both said controlling means and said brake mechanism and for making them alternatively operative, including electromagnetic coils, operative circuits for the electromotor and for each of said coils, and a single master control switch provided with fixed contacts connected with the operative circuits of the electromotor and the operative circuits of the coils respectively, and further provided with a master control lever carrying a central contact movable in all directions towards the fixed contacts, said movable contact being thus adapted to control and to close selectively the operative circuits of the electromotor and of the electromagnetic coils, respectively.

12. An electrically propelled wheel chair with two main driving wheels, comprising an electro motor, operative circuits for the same, a drive shaft driven by said electromctor, a friction drive roller for each of said main driving wheels normally in frictional engagement with the same, a combined electromagnetic coupling and brake mechanism between said friction drive rollers and said drive shaft, said coupling including a coupling member and a brake member, an operative circuit for each of said combined electromagnetic coupling and brake mechanisms and a single master control switch provided with fixed contacts connected with the operative circuits of the electromagnetic coupling and brake mechanism and further provided with a master control lever carrying a central contact movable in all directions towards the fixed contact, said movable contact being thus adapted to control and to close selectively the operative circuits of the electromotor and of the respective elect-rdmagnetic coupling and brake mechanisms.

13. An electrically propelled wheel chair with two main driving wheels, comprising an electromotor, operative circuits for the same, a drive shaft driven by said electromotor, a friction drive roller for each of said main driving wheels normally in frictional engagement with the same, a shaft section for each frictional driving roller, a combined electromagnetic coupling and braking mechanism between each of said shaft sections and drive shaft, said mechanism including engageable and disengageable coupling disks on said drive shaft and shaft sections respectively normally held in engagement. electromagnetic coils for moving one of said disks out of engagement with the other, a brake lining on said movable disk, a fixed brake lining adapted to engage said brake lining on the disk upon movement of the latter under the influence of an electromagnetic coil and spring means for returning the disk into its coupling position from its braking position, operative circuits for said electromagnetic coils and a single master control switch provided with fixed contacts connected with the operative circuits of the electrom-otor and of the electromagnetic coils, respectively, and further provided with a master contact lever carrying a central contact movable in all directions towards the fixed contact, said movable contact being thus adapted to control and to close selectively the operative circuits of the electromotor and of the electromagnetic coils respectively ARTHUR C. GUYTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 937,211 Holsman Q Oct. 19, 1909 1,540,170 Frick June 2, 1925 2,141,920 Lenhart Dec. 27, 1938 

